Murray needs to regain his composure fast ... having disposed of Rafael Nadal in three sets in the quarter final with an imperious display - albeit sealed by the Spaniard's retirement - Murray's game looks decidely flat against Cilic todayPhotograph: William West/AFP/Getty Images

Cilic has never before played a semi-final at a grand slam ... and the 21-year-old is beginning to look jaded as the cumulation of his exertions in reaching this round begin to showPhotograph: Cameron Spencer/Getty Images

Elsewhere in the tournament today ... Wild-card Justine Henin faces the unseeded Zheng Jie in the women's semis. Henin, the former world No1, is back at her first grand slam after 20 months in retirementPhotograph: Paul Crock/AP

After a hard fought three set match yesterday against Victoria Azarenka, Serena Williams must be hoping for an easier time in her semi-final against her sister's conqueror Na LiPhotograph: John Donegan/AP

Li was broken in the opening game of the match, but showed her battling qualities as she hung in the set and then finally broke Serena's serve to make it 5-5Photograph: Torsten Blackwood/AFP/Getty Images

But Serena finally broke Li's resistance and won the match with an ace. It was Williams' 50th victory at Melbourne and, if she beats Henin in the final, she will equal Billy-Jean King's record of 12 grand slam titlesPhotograph: Quinn Rooney/Getty Images